Devices useful for conducting chemical reactions have found widespread applications. Particularly, in chemical analyses, e.g. for the determination of constituents of body fluids like cholesterol in blood, devices containing fleece for the removal of constituents disturbing further analysis, e.g. cells, are commonly used. Furthermore, from EP 0 738 733 devices for separating nucleic acids from body fluids are known. However, this device is does not integrate sample preparation and detection. Integrated devices have the advantage of safety, protection from contamination and possibility of combination with other functions, e.g. detection.
More complex analyses need more sophisticated devices. For example, in U.S. Pat. No. 6,537,501 a cartridge is disclosed comprising micro fluidic flow channels and more extended compartments, like a waste collection container.
In JP 2004-163161 a device having a generally flat compartment with parallel upper and lower side walls containing a matrix for separating nucleic acids is disclosed. Therein, several layers of a fleece are inserted into the compartment and get uniformly compressed to increase extractability of nucleic acids. Therefore, the fluid flow is inhomogeneous. This has the consequence of lower binding capacity of the fleece and a need of higher fluid volume.
It was an object of the present invention to provide a device for improved robustness in use.